Transmission/reception of IP-based broadcast signals has been extended in digital broadcast systems. Specifically, the importance of Internet protocol (IP)-based broadcast signal transmission/reception environments has been emphasized in the mobile digital broadcast schemes, for example, DVB-NGH from among European broadcast standards or ATSC-MH from among North American standards. In addition, it is expected that a hybrid broadcast system designed to be interoperable with a broadcast network or an Internet network will be constructed in the next generation broadcast system.
In the hybrid broadcast system, since a scheme of transmitting data via an existing broadcast network and a scheme of transmitting data via a broadband network coexist, a scheme of processing the data is different from that in an existing broadcast receiver.
In addition, according to expansion of an IP-based broadcast system, an emergency alert message needs to be transmitted through a broadcast network. However, so far, a method for transmitting the emergency alert message has not been obviously defined.
Further, although many broadcast services could be provided due to expansion of the IP-based broadcast system, a method for enabling a viewer to efficiently search for a desired broadcast service has not been supported.
Furthermore, although a scheme of processing data included in broadcast signals can be expanded or changed according to expansion of the broadcast system, how to deal with such expansion or change of the data processing scheme in the broadcast system has not been provided.